Cleaning method

ABSTRACT

This invention relates to a method of cleaning using water, in which the water is softened and/or in which the deposition of hard water scale is diminished. The invention relates in particular to such a method carried out in a domestic environment. The invention also relate to textile article products on which is reversibly impregnated or deposited a water-softening agent and their use in such methods.

This invention relates to a method of cleaning using water, in which thewater is softened and/or in which the deposition of hard water scale isdiminished. The invention relates in particular to such a method carriedout in a domestic environment. The invention also relates to a textileproduct on which is reversibly impregnated or deposited at least onewater-softening agent and the use of such textile products in suchmethods.

It is well known that certain metal compounds, notably calciumcompounds, when present in water, have a significant effect on theproperties of the water. “Hard” water containing a significant loadingof soluble calcium and magnesium compounds and forms a scum with soap ordetergent, requiring a large amount of soap or detergent in order toform a lather. Scale deposits can readily form from such water, forexample on heating or pH change or evaporation.

There have been many proposals for the removal of metal ions fromaqueous solutions. In the industrial context proposals have includedfilter beds and polymeric filters for capturing heavy metal ions from anaqueous solution flowing within a passageway. Examples are given in EP992238A and GB 20869564A. In the domestic context chelating compositionscan be added to an aqueous washing solution and these can capture metalions, such as calcium ions. Examples of chelating compositions are givenin EP-A-892040. However in a multi-step washing process, such as thatcarried out by a clothes washing machine, it can be a problem that thechelating agent is discharged, with the water, at an intermediate stageof the process.

There is a need for a technology which can bind metal ions, at leastcalcium ions and preferably other metal ions in addition, in aconvenient manner, through the entire course of a cleaning procedure,including the rinse cycle of a ware washing machine, in particular aclothes' washing machine.

In accordance with a first aspect of the present invention there isprovided a cleaning method which employs a textile article immersed inwater, the textile article having at least one water-softening agentreversibly impregnated into, or deposited onto, the textile article.

The textile article may be so designed that the water-softening agent(s)are released over a period of time when exposed to water, for example,by partially or entirely coating the article with water-soluble polymersto delay the release of the water-softening agent(s).

One advantage of impregnating into or depositioning onto a textilearticle water-softening agent(s) is that discrete dosing is easilyachieved and that the dosage may be varied without the need of ameasuring system, as would be required for a liquid or powder. Forexample, half doses may be achieved by cutting or tearing the textilearticle in half. Alternatively multiple single doses may be provided ona single textile article which is marked, for example by printing by theuse of weakened tear line(s), to single doses, multiple doses orfractional doses. Alternatively the textile article may itself be setout in such a way, for example as a printed sheet, such that the useruses a size of textile article appropriate for the hardness of the waterused in the cleaning method.

We present as a further feature of the invention a kit of parts, the kitcomprising:

-   -   a) a textile article as defined herein and    -   b) a set of instructions telling the user of the textile article        to tear or cut a part of the textile article and to use the thus        removed part of the textile article in a cleaning method defined        herein.

Optionally the kit may also include a water hardness test.

Preferably detergent and/or bleach is absent from the textile article(“essentially free of detergent and/or bleach”).

Preferably the cleaning method is for cleaning household articles.

The method of cleaning may be a method of ware washing using a machine,for example a clothes' washing machine or a dishwashing machine.

In such methods the cleaning water is suitably produced by dissolutionof a liquid or solid cleaning concentrate, preferably by addition intothe machine, at or immediately after the start of the washing operation.Such concentrates suitably include one or more of an anionic surfactant,a non-ionic surfactant, an amphoteric surfactant or a cationicsurfactant. For machine washing anionic and non-ionic surfactants arepreferred.

A suitable anionic surfactant is an anionic organic surfactant, which isusually employed in a soluble salt form, preferably as an alkali metalsalt, especially as a sodium salt. Although other types of anionicdetergents may be utilized, such as higher fatty acyl sarcosides, alkylsulphosuccinates, alkyl ether sulphosuccinates, alkylamidesulphosuccinates, alkyl sulphosuccinates, alkyl sulphoacetates, alkylphosphates, alkyl ether phosphates, acyl isothionates, N-acyl tauratesand acyl lactylates, or conventional “soaps” of fatty acids, thepreferred anionic surfactants employed are those which are described asbeing of a sulphonate or sulphate type. These include linear higheralkylaryl sulphonates (for example alkylbenzene sulphonates), alkylsulphates, alkyl ether sulphates, alkylamidoether sulphates,alkylarylpolyether sulphates, monoglyceride sulphates, alkylsulphonates, alkylamido sulphonates, higher fatty alcohol sulphates,higher fatty alcohol polyalkoxylate sulphates, olefin sulphonates,∝-methyl ester sulphonates and paraffin sulphonates. An extensivelisting of anionic detergents, including such sulph(on)ate surfactants,is given at pages 25 to 138 of the text Surface Active Agents andDetergents, Vol. II, by Schwartz, Perry and Berch, published in 1958 byInterscience Publishers, Inc., and is incorporated herein by reference.Usually the higher alkyl group of such anionic surfactants is of 8 to24, especially 10 to 20 carbon atoms, preferably 12 to 18 carbon atoms,and the alkoxylate content of such anionic surfactants that arealkoxylated (preferably ethoxylated or ethoxylated/ propoxylated) is inthe range of 1 to 4 alkoxy groups per mole.

One preferred class of anionic surfactants comprise the alkali metal(preferably sodium) alkyl sulphates, preferably having linear C₁₂₋₁₈alkyl groups.

Another preferred class of anionic surfactants comprise alkali metal(preferably sodium) alkylaryl sulphonates (especially alkylbenzenesulphonates), preferably having linear C₁₀₋₁₃ alkyl groups.

A preferred non-ionic surfactant is a condensation product of a higherfatty alcohol or alkyl phenol with a lower alkylene oxide, such asethylene oxide or a mixture of ethylene oxide and propylene oxide. Insuch non-ionic surfactants the higher fatty moiety will normally be of 7to 16 carbon atoms and there will usually be present from 3 to 20,preferably 4 to 15 moles of alkylene oxide per mole of higher fattyalcohol.

Another class of non-ionic surfactants that could be used are sorbitanesters of fatty acids having from 10 to 24 carbon atoms, for examplesorbitan mono-oleate.

Amphoteric surfactants which may be used include amphoteric betainesurfactant compounds having the following general formula:

wherein R is a hydrophobic group which is an alkyl group containing from10 to 22 carbon atoms, preferably from 12 to 18 carbon atoms, analkylaryl or arylalkyl group containing a similar number of carbon atomswith a benzene ring being treated as equivalent to about 2 carbon atoms,and similar structures interrupted by amido or ether linkages; each R₁is an alkyl group containing from 1 to 3 carbon atoms; and R₂ is analkylene group containing from 1 to 6 carbon atoms.

Examples of cationic surfactants which may be used include quaternaryammonium compounds and salts thereof, including quaternary ammoniumcompounds which also have germicidal activity and which may becharacterized by the general structural formula:

when at least one of R₁, R₂, R₃ and R₄ is a hydrophobic, aliphatic, arylaliphatic or aliphatic aryl group containing from 6 to 26 carbon atoms,and the entire cationic portion of the molecule has a molecular weightof at least 165. The hydrophobic groups may be long-chain alkyl,long-chain alkoxy aryl, long-chain alkyl aryl, halogen-substitutedlong-chain alkyl aryl, long-chain alkyl phenoxy alkyl or aryl alkyl. Theremaining groups on the nitrogen atoms, other than the hydrophobicradicals, are generally hydrocarbon groups usually containing a total ofno more than 12 carbon atoms. The radicals R₁, R₂, R₃ and R₄ may bestraight chain or may be branched, but are preferably straight chain,and may include one or more amide or ester linkages. The radical X maybe any salt-forming anionic radical.

Examples of quaternary ammonium salts within the above descriptioninclude the alkyl ammonium halides such as cetyl trimethyl ammoniumbromide, alkyl aryl ammonium halides such as octadecyl dimethyl benzylammonium bromide, and N-alkyl pyridinium halides such as N-cetylpyridinium bromide. Other suitable types of quaternary ammonium saltsinclude those in which the molecule contains either amide or esterlinkages, such as octyl phenoxy ethoxy ethyl dimethyl benzyl ammoniumchloride and N-laurylcocoaminoformylmethyl)-pyridinium chloride. Othereffective types of quaternary ammonium compounds which are useful asgermicides includes those in which the hydrophobic radical ischaracterized by a substituted aromatic nucleus as in the case oflauryloxyphenyltrimethyl ammonium chloride, cetylaminophenyltrimethylammonium methosulphate, dodecylphenyltrimethyl ammonium methosulphate,dodecylphenyltrimethyl ammonium chloride and chlorinateddodecylphenyltrimethyl ammonium chloride.

Preferred quaternary ammonium compounds which act as germicides andwhich are useful in the present invention include those which have thestructural formula:

wherein R₂ and R₃ are the same or different C₈-Cl₂alkyl, or R₂ isC₁₂-C₁₆alkyl, C₈-C₁₈alkylethoxy, C₈-C₁₈alkyl-phenolethoxy and R₂ isbenzyl, and X is a halide, for example chloride, bromide or iodide, ormethosulphate. The alkyl groups R₂ and R₃ may be straight chain orbranched, but are preferably substantially linear. It is a preferredfeature of the invention to use cationic surfactant, such as thosedescribed above, in combination with a method of the invention asdescribed herein, or with a an article for use in such methods, sincethe germicidal activity of such compounds is improved in softer water.

In any method of the invention, a mixture of two or more surfactants maybe used. Other known surfactants not particularly described above mayalso be used. Such surfactants are described in McCutcheon's Detergentsand Emulsifiers, North American Edition, 1982; Kirk-Othmer,Encyclopaedia of Chemical Technology, 3rd Ed., Vol. 22, pp 346-387.

The cleaning method may be a manual method, for example using ahand-cloth or mop, and an open vessel, for example a bucket or bowl.Thus, the cleaning method could be a method of cleaning a hard surface,for example a window, tiled surface, shower screen, tableware andkitchenware, a sanitaryware article, for example a shower screen,lavatory, wash basin or sink, a car (defined herein as a “householdarticle”) or a kitchen worktop.

In such methods the cleaning agent is dissolved in water prior to thestart of cleaning. The cleaning agent may comprise an anionic surfactantand/or a non-ionic surfactant, as described above. Additionally oralternatively, the cleaning agent may include one or more of anamphoteric surfactant and a cationic surfactant, as described above.

A composition used in the invention may optionally include one or moreconventional additives known to be useful in cleaning compositionsincluding bleaching agents, viscosity modification agents, fragrances(natural or synthetically produced), foaming or foam-control agents,solvents, fillers, colouring agents, and in the case of compositions forfabric washing, fabric conditioning agents, enzymes, hydrotropes and dyeanti-redeposition agents. If the composition does not contain a cationicsurfactant having germicidal properties as detailed above, a germicidalagent may be incorporated as an optional ingredient into the cleaningagents used in the invention. Examples are phenolic group containingcompounds such as o-phenyl-phenol, o-benzyl[p-chlorophenol] and4-tertamylphenol.

The textile article acts as a water softener within a vessel containingwater, for example a bucket, sink or ware-washing machine. The cleaningagent(s) present in the water can work more effectively, and/or thevessel is soiled or scaled less, whether by soap scum or byencrustations or by watermarks left when droplets on a surfaceevaporate. The textile article itself can be used as the means forcleaning.

Preferably the textile article is able to move freely within the waterused in the cleaning method. Thus, it is preferably not in the form of afilter or like body, retained in a fixed orientation, or mounted on aframe.

The textile article may be, for example, a woven, knitted or non-wovensheet. The sheet may if wished be secured to one or more further sheets,which may be of the same or different material, forming a ply. In onefeature of the invention the water-softening agent(s) is held betweenthe ply. Alternatively the textile article may be in the form of a thickyarn, or braid. Alternatively it may be in the form of fibres orfilaments, which may, for example, be tied together in a bundle, forexample in a tassel or pom-pom, or retained in a water-permeable bag.

Most preferably the textile article is a fabric sheet of relatively openform, for example a non-woven fabric or a woven fabric of scrim form.Preferably a number of fabric sheets are joined together and aredemonstrated via a line of weakness.

It will be appreciated that the textile article can improve cleaning byacting as a water softener, by facilitating capture of metal ions,notably calcium ions, from the water.

Preferably the textile article is also able to bind magnesium ions. Mostpreferably it is able to bind further ions, for example copper and ironions. Preferably the moieties which are able to bind calcium ions arealso able to bind such further ions, notably magnesium ions.

A dye could be employed to give a colour change, on exhaustion of theavailable water-softening agent(s) on the textile article.

Suitable water-softening agents are those selected from below. Suchcomponents will provide three main types of method of action, describedbelow.

1) Ion exchange agents—such agents include alkali metal (preferablysodium) aluminosilicates either crystalline, amorphous or a mixture ofthe two. Such aluminosilicates generally have a calcium ion exchangecapacity of at least 50 mg CaO per gram of aluminosilicate, comply witha general formula:0.8-1.5 Na₂O.Al₂O₃.0.8-6 SiO₂and incorporate some water. Preferred sodium aluminosilicates within theabove formula contain 1.5-3.0 SiO₂ units. Both amorphous and crystallinealuminosilicates can be prepared by reaction between sodium silicate andsodium aluminate, as amply described in the literature.

Suitable crystalline sodium aluminosilicate ion-exchange detergencybuilders are described, for example, in GB 1429143 (Procter & Gamble).The preferred sodium aluminosilicates of this type are the well knowncommercially available zeolites A and X, and mixtures thereof. Also ofinterest is zeolite P described in EP 384070 (Unilever).

Another class of compounds are the layered sodium silicate builders,such as are disclosed in U.S. Pat. No. 4,464,839 and U.S. Pat. No.4,820,439 and also referred to in EP-A-551375.

These materials are defined in U.S. Pat. No. 4820439 as beingcrystalline layered, sodium silicate of the general formulaNaMSi_(x)O_(2x+1).YH₂Owherein

-   -   M denotes sodium or hydrogen,    -   x is from 1.9 to 4 and y is from 0 to 20.

Literature references describing the preparation of such materialsinclude Glastechn. Ber. 37,194-200 (1964), Zeitschrift fur Kristallogr.129, 396-404 (1969), Bull. Soc. Franc. Min. Crist., 95, 371-382 (1972)and Amer. Mineral, 62, 763-771 (1977). These materials also function toremove calcium and magnesium ions from water. Also covered are salts ofzinc which have also been shown to be effective water softening agents.

2) Ion capture agents—agents which prevent metal ions from forminginsoluble salts or reacting with surfactants, such as polyphosphate,monomeric polycarbonates, such as citric acid or salts thereof, EDTA,algins, alginates, imidodisuccinic acid or a salt thereof (such asBaypure CX100) and glucohepatanoic acid or a salt thereof.

3) Anti-nucleating agents—agents which prevent seed crystal growth, suchas polycarbonate polymers, such as polyacrylates, acrylic/maleiccopolymers, and acrylic phosphonates, polyaspartic acid polymers or asalt thereof (such as Baypure DS100) and 2-acrylamido-2-methyl propanesulfonic acid polymers.

It will be appreciated that certain actives may perform more than onefunction, such as polyaspartic acid polymers, which as well as beingantinucleating agents are also effective as ion capture agents.

Such ingredient(s) may be reversibly impregnated or deposited on thetextile article by dosing a solution to the textile article andevaporating the solute. Spray drying techniques may be employed. Ioniccharge may also be employed to reversibly bind anionic ionisableingredients to the textile article.

The textile article can have bound to it such ingredients in the form ofparticles of a material, as described above, with those particles notbeing released from the textile article in use.

Alternatively the textile article could carry on it particles of amaterial, as described above, with those particles being washed from thetextile article, and dissolved or dispersed in the wash water, in use.

Alternatively there can be a hybrid system in which some such particlesremain on the textile article and some are washed off, during themethod. 10782P6WO

The washing off of particles of such materials may be rapid in water ormay be slow/progressive. A slow-release system may be attractive inobtaining good activity, for example calcium binding, throughout acleaning method.

In accordance with a second aspect of the invention there is provided amethod of cleaning in a ware washing machine, the method includingsoftening the water in the machine, using a textile article having atleast one water-softening agent reversibly impregnated into, ordeposited onto, the textile article.

In the second aspect the textile article may be such that water issoftened in the wash cycle. Preferably it is softened in the rinsecycle. Most preferably it is softened both in the wash and in the rinsecycles.

According to a third feature of the invention there is provided atextile article having at least one water softening agent reversiblyimpregnated into, or deposited onto, the textile article.

The invention will now be described, by way of embodiment, withreference to the following examples.

EXAMPLE 1

A 25 cm² cellulose fibre non-woven sheet was immersed into a beaker of 6g of Accusol 445N (polyacrylate) dissolved in 100 g of water. The sheetwas removed after being saturated with the Accusol 444N solution andplaced on a hard surface at ambient conditions for 24 hours. After 24hours the non-woven sheet was found to be dry.

1. A cleaning method which employs a textile article immersed in water,the textile article having at least one water-softening agent reversiblyimpregnated into or deposited onto the textile article.
 2. A method asclaimed in claim 1, wherein the textile article changes colour onexhaustion of the available water-softening agent.
 3. A method asclaimed in claim 1, wherein the textile article is used as a materialfor wiping a surface to be cleaned.
 4. A method of cleaning in a warewashing machine, the method including softening the water in themachine, using a textile article having at least one water-softeningagent reversibly impregnated into or deposited onto the textile article.5. A method according to claim 1, wherein the water-softening agentcomprises calcium-binding particles which dissolve or disperse in waterwith which the textile article is in contact.
 6. (canceled)
 7. A methodaccording to claim 1, in which the method comprises removing scale ordiminishing its deposition.
 8. A method according to claim 1, whereinthe textile article is a cloth.
 9. A method according to claim 8,wherein the textile article is a non-woven sheet.
 10. A method accordingto claim 1, wherein the textile article comprises multiple doses.
 11. Amethod according to claim 10, wherein the textile article is marked intosingle doses.
 12. A method according to claim 6 wherein the textilearticle releases a water softening agent in the rinse cycle of the warewashing machine.
 13. A method of improving the operation of a warewashing machine, by softening the water therein, the method comprisingusing in the machine a textile article having at least onewater-softening agent reversibly impregnated into or deposited onto thetextile article.
 14. A method according to claim 13 wherein the textilearticle softens the water of the ware washing machine.
 15. A textilearticle having at least one water softening agent reversibly impregnatedinto or deposited onto the textile article.
 16. A textile articleaccording to claim 15, wherein the textile article is marked into singledoses.
 17. A textile article according to claim 16, wherein the textilearticle is marked into single doses by means of printing or weakenedtear line(s).
 18. A kit of parts, the kit comprising: a textile articlehaving at least one water softening agent reversibly impregnated into ordeposited onto the textile article, and a set of instructions tellingthe user of the textile article to tear or cut a part of the textilearticle and to use the thus removed part of the textile article in acleaning method according to claim
 1. 19. A kit of parts as claimed inclaim 18, wherein the kit additionally comprises a water hardness test.20. A method according to claim 4 wherein the water-softening agentcomprises calcium-binding particles which dissolve or disperse in waterwith which the textile article is in contact.